| Titles |
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English :
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Improvement of fertility in Ossimi ewes during summer mating season using a GnRH analogue
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Arabic :
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تحسين الخصوبة في النعاج الاوسيمى اثناء موسم التلقيح الصيفى باستخدام عقار شبية هرمون GnRH
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| Abstract |
Thirty Ossimi ewes. (aged 4-6 years with an average 37.2 kg. body weight) were used to verify the effect of GnRH ana1ogue injection during summer mating season (May, where air temperature was 3,9.02 °C and relative humidity was 54.68 %.). These environmental conditions were hot enough to cause a marked heat stress in ewes during mating season and may decline their fertility, although these ewes had previously good reproductive history through all their reproductive live (regular lambing) in other seasons of the year. The experimenta1 animals were divided into 3 equal groups, first group (T1) was injected subcutaneously with 100 μg of GnRH per ewe at the beginning of the breeding season, second group (T2) was injected with 50 μg of GnRH per ewe, while the third group (control) was injected with 100 μg saline solution per ewe. Ewes showed oestrus signs were naturally mated twice daily by a fertile ram of the same breed. All animals were used to monitor progesterone concentrations. The blood samples were collected immediately before summer- mating season, at the 3rd day postmating, then twice weekly till day 42 of the mating season.
The aim of this work was to estimate the influence of GnRH injection at the time of breeding on fertility during summer mating season among ewes characterized. ,with previously regular reproductive status. The present study achieved 40 and 50 % lambing rate when animals injected with 50 or100 μg GnRH (analogue) respectively, while lambing rate was10 % only in the control group.
The obtained results revealed that, lambing rate was higher (p < 0.01) in T1 (50%) thal1 in T 2 (40 %) and control group (10 %), while the number of lambs born was higher (p<0.01) in T1 than in T2 and control ones6, 4 and 1 lambs out of 10 ewes, respectively). Serum progesterone concentrations were significantly (p < 0.01) increased in the treated pregnant ewes than in the control pregnant ones.
Under Upper Egypt conditions, it could be concluded that GnRH injection could be safely used immediately before summer mating season to induce oestrus and increase rate of pregnancy and lambing II well increase the number of lambs born.
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| Publication year |
2002
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| Availability location |
معهد بحوث الانتاج الحيوانى-7 شارع نادى الصيد - الدقى - الجيزة
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| Availability number |
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| Organization Name |
Animal Production Research Institute (APRI)
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| City |
الزقازيق
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| serial title |
Zagazig, Journal Agricultural Research
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| Author(s) from ARC |
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| External authors (outside ARC) |
حسن عبد الغنى دغش
جامعة اسيوط
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| Agris Categories |
Animal physiology - Reproduction
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AGROVOC
TERMS |
Copulation.
Ewes.
Fertility.
Gnrh.
Heat stress.
Seasons.
Summer.
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| Publication Type |
Journal
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